The present invention relates to the use of mixtures of micronised organic UV filters in protecting human and animal skin and hair against the damaging effect of UV radiation and to their use in cosmetic and pharmaceutical formulations.
It is known that certain organic UV filters, for example sparingly soluble benzotriazole or triazine compounds, exhibit pronounced UV filtering properties when they are in the form of single compounds in micronised form. By virtue of their specific, substance-typical properties, however, they only ever absorb, reflect or scatter a certain portion of the damaging UV range.
There is strong interest in light-protective filters that cover a broad UV spectrum and thus offer better UV protection.
The aim of the present invention is therefore to find micronised organic UV filters that cover a broader portion of the UV range, with which it is thus possible to achieve better UV protection.
It has now been found, surprisingly, that mixtures of at least two micronised UV filters are able to achieve that aim.
The present invention therefore relates to the use of mixtures of micronised organic UV filters in protecting human and animal skin and hair against the damaging effect of UV radiation.
UV filters suitable for use according to the invention are organic, in some cases sparingly soluble, compounds, for example triazine derivatives, especially hydroxyphenyltriazine compounds or benzotriazole derivatives, amides containing a vinyl group, cinnamic acid derivatives, sulfonated benzimidazoles, Fischer base derivatives, diphenylmalonic acid dinitriles, oxalyl amides, camphor derivatives, diphenyl acrylates, para-aminobenzoic acid (PABA) and derivatives thereof, salicylates, benzophenones and further classes of substances known as UV filters.
Preferred triazine derivatives suitable for use according to the invention correspond to formula 
wherein
R1, R2 and R3 are each independently of the others hydrogen; OH; C1-C18alkoxy; xe2x80x94NH2; xe2x80x94NHxe2x80x94R4; xe2x80x94N(R4)2; xe2x80x94OR4,
R4 is C1-C5alkyl; phenyl; phenoxy; anilino; pyrrolo, wherein phenyl, phenoxy, anilino and pyrrolo are unsubstituted or may be substituted by one, two or three OH groups, carboxy, xe2x80x94COxe2x80x94NH2, C1-C5alkyl or C1-C5alkoxy; a methylidene-camphor group; a group of formula xe2x80x94(CHxe2x95x90CH)mC(xe2x95x90O)xe2x80x94OR4; a group of formula 
or a corresponding alkali metal, ammonium, mono-, di- or tri-C1-C4alkylammonium, mono-, di- or tri-C2-C4alkanolammonium salt, or a C1-C3alkyl ester thereof; or a radical of formula 
R5 is hydrogen; C1-C5alkyl unsubstituted or substituted by one or more OH groups; C1-C5alkoxy; amino; mono- or di-C1-C5alkylamino; M; a radical of formula 
wherein
Rxe2x80x2, Rxe2x80x3 and Rxe2x80x2xe2x80x3 are each independently of the others C1-C14alkyl unsubstituted or substituted by one or more OH groups;
R6 is hydrogen; M; C1-C5alkyl; or a radical of formula xe2x80x94(CH2)m2xe2x80x94Oxe2x80x94T1;
M is a metal cation;
T1 is hydrogen; or C1-C8alkyl;
m is 0 or 1;
m2 is from 1 to 4; and
m3 is from 2 to 14.
Further preferred triazine derivatives suitable for use according to the invention correspond to formula 
wherein
R7 and R8 are each independently of the other C1-C18alkyl; C2-C18alkenyl; a radical of formula xe2x80x94CH2xe2x80x94CH(xe2x80x94OH)xe2x80x94CH2xe2x80x94Oxe2x80x94T1; or
R7 and R8 are a radical of formula 
R9 is a direct bond; a straight-chain or branched C1-C4alkylene radical or a radical of formula xe2x80x94Cm1H2m1xe2x80x94Oxe2x80x94;
R10, R11 and R12 are each independently of the others C1-C18alkyl; C1-C18alkoxy or a radical of formula 
R13 is C1-C5alkyl;
m1 is from 1 to 4;
p1 is from 0 to 5;
A1 is a radical of formula 
or of formula 
R14 is hydrogen; C1-C10alkyl, xe2x80x94(CH2CHR16xe2x80x94O)n1xe2x80x94R15; or a radical of formula xe2x80x94CH2xe2x80x94CH(xe2x80x94OH)xe2x80x94CH2xe2x80x94Oxe2x80x94T1;
R15 is hydrogen; M; C1-C5alkyl; or a radical of formula xe2x80x94(CH2)m2xe2x80x94Oxe2x80x94(CH2)m3xe2x80x94T1;
R16 is hydrogen; or methyl;
T1 is hydrogen; or C1-C8alkyl;
Q1 is C1-C18alkyl;
M is a metal cation;
m2 and m3 are each independently of the other from 1 to 4; and
n1 is from 1 to 16.
Very especially preferred triazine derivatives of formula (2) correspond to formulae 
wherein
R17 and R18 are each independently of the other C3-C18alkyl; or xe2x80x94CH2xe2x80x94CH(xe2x80x94OH)xe2x80x94CH2xe2x80x94Oxe2x80x94T1;
R19 is C1-C10alkyl or a radical of formula 
R20 is hydrogen; M; C1-C5alkyl; xe2x80x94NHxe2x80x94C1-C5alkyl; preferably xe2x80x94NH-tert-alkyl; or a radical of formula xe2x80x94(CH2)mxe2x80x94Oxe2x80x94T2;
T1 and T2 are each independently of the other hydrogen; or C1-C5alkyl; and
m is from 1 to 4.
Of very special interest are compounds of formulae (2a) and (2b) wherein
R17 and R18 are each independently of the other C1-C18alkyl; or xe2x80x94CH2xe2x80x94CH(xe2x80x94OH)xe2x80x94CH2xe2x80x94Oxe2x80x94T1;
R19 is C1xe2x80x94C10alkyl;
and compounds of formulae (2c) and (2d) wherein
R17 and R18 are each independently of the other C1-C18alkyl or xe2x80x94CH2xe2x80x94CH(xe2x80x94OH)xe2x80x94CH2xe2x80x94Oxe2x80x94T1; and
T1 is hydrogen; or C1-C5alkyl.
Of very great interest are triazine compounds of formulae (2a)-(2d) wherein
R17 and R18 have the same meaning.
Further interesting triazine compounds suitable for use according to the invention correspond to formula 
wherein
R21 is C1-C30alkyl; C2-C30alkenyl; C5-C12cycloalkyl unsubstituted or mono or poly-substituted by C1-C5alkyl; C1-C5alkoxy-C1-C12alkyl; amino-C1-C12alkyl; C1-C5-monoalkylamino-C1-C12alkyl; C1-C5dialkylamino-C1-C12alkyl; a radical of formula 
wherein
R22, R23 and R24 are each independently of the others hydrogen, xe2x80x94OH; C1-C30alkyl, C2-C30alkenyl,
R25 is hydrogen; or C1-C5alkyl;
m1 is 0 or 1; and
n1 is from 1 to 5.
Preferred compounds correspond to formula 
wherein
R26 is 
or
xe2x80x94O-2-ethylhexyl; xe2x80x94Oxe2x80x94(CH2)3xe2x80x94N(C2H5)2; 
and
r and s are each independently of the other from 0 to 20.
Examples of triazine derivatives suitable for use according to the invention correspond to the formulae 
also 2,4,6-tris(diisobutyl-4xe2x80x2-aminobenzalmalonate)-s-triazine and 2,4-bis(diisobutyl-4-amino-benzalmalonate)-6-(4xe2x80x2-aminobenzylidenecamphor)-s-triazine.
Triazine compounds suitable for use according to the invention that are likewise preferred are described in EP-A-654 469, e.g. the compound of formula 
Triazine compounds especially suitable for use according to the invention are described, for example, in EP-A-0 818 450, e.g. the compound of formula 
Very especially preferred triazine derivatives suitable for use according to the invention correspond to formula 
wherein
R27, R28 and R29 are each independently of the others a radical of formula 
or
R30 is hydrogen; an alkali metal; an ammonium group xe2x80x94N(R33)4,
R33 is hydrogen, C1-C5alkyl; or a polyoxyethylene radical that has from 1 to 10 ethylene oxide units and the terminal OH group can be etherified with a C1-C5alcohol;
R31 is hydrogen; xe2x80x94OH; or C1-C6alkoxy;
R32 is hydrogen or xe2x80x94COOR30; and
n is 0 or 1.
When R30 is an alkali metal, it is especially potassium or more especially sodium. (R33)4 is especially a mono-, di- or tri-C1-C4alkylammonium salt, a mono-, di- or tri-C2-C4alkanol-ammonium salt or a C1-C3alkyl ester thereof.
When R33 is a C1-C3alkyl group, it is especially a C1-C2alkyl group, more especially a methyl group, and when R33 is a polyoxyethylene radical, that radical contains especially from 2 to 6 ethylene oxide units.
Preferred benzotriazole compounds suitable for use according to the invention correspond to formula 
wherein
T1 is C1-C5alkyl or preferably hydrogen; and
T2 is C1-C5alkyl, preferably tert-butyl, or phenyl-substituted C1-C4alkyl, especially xcex1,xcex1-dimethylbenzyl.
A further preferred class of benzotriazole compounds suitable for use according to the invention corresponds to formula 
wherein
T2 is as defined for formula (26).
Further, especially preferred benzotriazole compounds suitable for use according to the invention correspond to formula 
wherein
T2 is as defined for formula (26) and is preferably methyl, tert-butyl or iso-octyl.
Preferred vinyl-group-containing amides suitable for use according to the invention correspond to formula
R33xe2x80x94(Y)mxe2x80x94COxe2x80x94C(R34)xe2x95x90C(R35)xe2x80x94N(R36)(R37),xe2x80x83xe2x80x83(29)
wherein
R33 is C1-C5alkyl, preferably methyl or ethyl, or phenyl unsubstituted or substituted by one, two or three of the radicals OH, C1-C5alkyl, C1-C5alkoxy and COxe2x80x94OR33;
R34, R35, R36 and R37 are each independently of the others C1-C5alkyl, preferably methyl or ethyl; or hydrogen;
Y is xe2x80x94NH or xe2x80x94Oxe2x80x94; and
m is as defined above.
Preferred compounds of formula (29) are 4-methyl-3-penten-2-one, ethyl 3-methylamino-2-butenoate, 3-methylamino-1-phenyl-2-buten-1-one and 3-methylamino-1-phenyl-2-buten-1-one.
Preferred cinnamic acid amides suitable for use according to the invention correspond to formula 
wherein
R38 is hydrogen or C1-C5alkoxy, preferably methoxy or ethoxy;
R39 is hydrogen or C1-C5alkyl, preferably methyl or ethyl; and
R40 is xe2x80x94(CONH)m-phenyl, wherein m is as defined above and the phenyl group is unsubstituted or substituted by one, two or three of the radicals OH, C1-C3alkyl, C1-C3alkoxy and COxe2x80x94OR30.
R40 is preferably phenyl, 4-methoxyphenyl or the phenylaminocarbonyl group.
Further preferred cinnamic acid derivatives are 2-ethylhexyl-4-methoxy-cinnamate or -isoamylate or inter alia the cinnamic acid derivatives disclosed in U.S. Pat. No. 5,601,811 and WO 97/00851.
Preferred sulfonated benzimidazoles suitable for use according to the invention correspond to formula 
wherein
M is hydrogen or an alkali metal, preferably sodium, an alkaline earth metal, e.g. magnesium or calcium, or zinc.
Preferred Fischer base aldehydes suitable for use according to the invention correspond to formula 
wherein
R41 is hydrogen; C1-C5alkyl; C1-C18alkoxy; or halogen;
R42 is C1-C8alkyl; C5-C7cycloalkyl; or C6-C10aryl;
R43 is C1-C18alkyl or a radical of formula 
R44 is hydrogen; or a radical of formula 
R45 is 
C1-C18alkoxy: or a radical of formula 
R46 and R47 are each independently of the other hydrogen; or C1-C5alkyl;
R48 is hydrogen; C1-C5alkyl; C5-C7cycloalkyl; phenyl; phenyl-C1-C3alkyl;
R49 is C1-C18alkyl;
X is Hal; a radical of formula 
and
n is 0; or 1.
Further compounds that can preferably be used correspond to formula 
wherein
R50, R51, R52, R53, R54 are each independently of the others hydrogen, C1-C8alkyl or C5-C10-cycloalkyl;
R55 is hydrogen; C1-C8alkyl; C5-C10cycloalkyl; hydroxy; C1-C8alkoxy; COOR56; or CONR57R58;
R56, R57 and R58 are each independently of the others hydrogen or C1-C6alkyl;
X and Y are each independently of the other hydrogen, xe2x80x94CN; CO2R59; CONR59R60; or COR59; it being possible for the radicals X and Y additionally to be a C1-C8alkyl radical, a C5-C10alkyl radical, especially phenyl, or a heteroaryl radical having 5 or 6 ring atoms, it also being possible for X and Y or
R50 together with one of the radicals X and Y to be the radical for completing a 5- to 7-membered ring which may contain up to 3 hetero atoms, especially oxygen and/or nitrogen. it being possible for the ring atoms to be substituted especially by exo-cyclically double-bonded oxygen (keto oxygen) and/or by C1-C8alkyl and/or by C5-C10-cycloalkyl radicals and/or to contain Cxe2x95x90C double bonds;
Z is hydrogen; ammonium; an alkali metal ion; especially lithium, sodium, potassium, xc2xd equivalent of an alkaline earth metal ion, preferably calcium, magnesium, or the cation of an organic nitrogen base used for neutralisation of the free acid group,
R59 and R60 are each independentlyof the other hydrogen, C1-C8alkyl or C5-C10cycloalkyl; and
n and m are each independently of the other 0 or 1.
Preferred diphenylmalonic acid nitrites suitable for use according to the invention correspond to formula 
wherein
R61 and R62 are each independently of the other C1-C12alkyl; or C1-C12alkoxy; and
n is 0-3
Further organic UV filters suitable for use according to the invention correspond to formula 
wherein
R63 and R64 are each independently of the other C1-C5alkyl, especially ethyl.
Further preferred chemical compound classes of UV filters suitable for use according to the invention are:
p-aminobenzoic acid derivatives (PABA), especially 2-ethylhexyl-4-dimethylamino-benzoate;
salicylic acid derivatives, especially 2-ethylhexyl salicylates; homosalates; and isopropyl salicylates;
benzophenone derivatives, especially benzophenone-2, -3 and -4;
dibenzoylmethane derivatives, especially 1-(4-tert-butylphenyl)-3-(4-methoxyphenyl)-propane-1,3-dione or butylmethoxydibenzoylmethane;
diphenyl acrylates, especially 2-ethylhexyl-2-cyano-3,3-diphenyl acrylate, ethyl 2-cyano-3,3xe2x80x2-diphenyl acrylate and 3-(benzofuranyl)-2-cyanoacrylate;
3-imidazol-4-yl-acrylic acid and 3-imidazol-4-yl acrylate;
benzofuran derivatives, especially the p-aminophenylbenzofuran derivatives disclosed in EP-A-582 189, U.S. Pat. No. 5,338,539 and U.S. Pat. No. 5,518,713;
camphor derivatives, especially 3-(4xe2x80x2-methyl)benzylidenebornan-2-one, 3-benzylidene-bornan-2-one, N-[2(and 4)-2-oxyborn-3-ylidenemethyl)benzyl]acrylamide polymer, 3-(4xe2x80x2-trimethylammonium)benzylidenebornan-2-one methyl sulfate, 3,3xe2x80x2-(1,4-phenylene-dimethine)-bis(7,7-dimethyl-2-oxobicyclo[2.2.1]heptane-1-methanesulfonic acid) and salts thereof, 3-(4xe2x80x2-sulfo)benzylidenebornan-2-one and salts thereof, and also
menthyl o-aminobenzoate.
Preferably the following mixtures of organic UV filters are used:
mixtures of methylene bis-benzotriazolyl tetramethylbutylphenol and octyl triazone;
mixtures of octyl triazone and methylene bis-benzotriazolyl tetramethylbutylphenol;
mixtures of 2-[(2,4-methoxy)-phenyl]4,6-bis[(2-hydroxy-4-methoxy)-phenyl]-(1,3,5)-triazine and methylene bis-benzotriazolyl tetramethylbutylphenol;
mixtures of methylene bis-benzotriazolyl tetramethylbutylphenol and dioctyl butamido-triazone;
mixtures of methylene bis-benzotriazolyl tetramethylbutylphenol and octyl-2,2xe2x80x2-methylene bis[6-(2H-benzotriazol-2-yl))-4-methyl-phenol,
mixtures of octyl triazone and tris-resorcinyl triazine;
mixtures of 2,2xe2x80x2-methylene bis(6-(2H-benzotriazol-2-yl)-4-methyl-phenol, octyl triazone
and the compound of formula 
mixtures of 2,2xe2x80x2-methylene bis[6-(2H-benzotriazol-2-yl)-4-methyl-phenyol, octyl triazone
and the compound of formula 
mixtures of methylene bis-benzotriazolyl tetramethylbutylphenol, octyl triazone and the compound of formula 
mixtures of methylene bis-benzotriazolyl tetramethylbutylphenol and the compound of 
mixtures of methylene bis-benzotriazolyl tetramethylbutylphenol, dioctyl butamido-triazone and the compound of formula (37).
In the radicals defined above, C1-C18alkyl denotes straight-chain or branched alkyl radicals, e.g. methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, amyl, isoamyl or tert-amyl, heptyl, octyl, isooctyl, nonyl, decyl, undecyl, dodecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl and octadecyl.
C1-C18Alkoxy radicals are straight-chain or branched alkyl radicals, e.g. methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, sec-butoxy, tert-butoxy, amyloxy, isoamyloxy or tert-amyloxy, heptyloxy, octyloxy, isooctyloxy, nonyloxy, decyloxy, undecyloxy, dodecyloxy, tetradecyloxy, pentadecyloxy, hexadecyloxy, heptadecyloxy and octadecyloxy.
C2-C18Alkenyl is e.g. allyl, methallyl, isopropenyl, 2-butenyl, 3-butenyl, isobutenyl, n-penta-2,4-dienyl, 3-methyl-but-2-enyl, n-oct-2-enyl, n-dodec-2-enyl, isododecenyl, n-dodec-2-enyl or n-octadec4-enyl.
The mixtures of micronised organic UV filters suitable for use according to the invention can be prepared in various ways:
In a first method, at least two of the above-mentioned organic UV filters can be mixed, as single substances, during the process for the preparation of the microparticles (micronisation).
A further possible preparation method comprises intimately mixing together the single substances of the UV filters which have already been micronised.
A third possible preparation method comprises melting together at least two of the UV filters mentioned above. After the melt has cooled, a homogeneous composite is obtained, which is micronised in customary manner.
The invention relates also to the homogeneous composites of at least two organic UV filters.
The invention relates also to composites obtainable by melting one or more inorganic micropigments into one or more organic UV filters.
Examples of micropigments are TiO2, ZnO, iron oxides and other inorganic oxides, mica and other suitable inorganic minerals, and also titanium salts, alkaline earth metal salts and zinc salts of organic acids.
As a result, the undesirable photocatalytic properties of some of those inorganic micro-pigments (TiO2, ZnO) can be suppressed at the same time and their positive properties additionally fully utilised.
Advantageously the above-mentioned inorganic UV filters are melted into methylene bis-benzotriazolyl tetramethylbutylphenol The composite so obtained is then micronised in customary manner.
The invention relates also to composites obtainable by melting at least two electrically neutral organic UV filters with cationically or anionically charged compounds.
For that purpose, cationically or anionically charged compounds are melted with the corresponding organic, electrically neutral UV filters and then cooled. By means of that process it is possible in the subsequent micronisation step to prepare organic UV filter pigments that are permanently provided with a positive or negative charge. Such provision effectively prevents the aggregation of the micronised particles in the sunscreen preparations, which may occur when the particle diameter is  less than 1 xcexcm. Providing the particles with a xe2x80x9ccoatingxe2x80x9d having a repellent effect, which is otherwise customary, is then superfluous in some cases.
As cationically or anionically charged compounds it is possible to use UV filters or other compounds having one or more cationic or anionic groupings, e.g.
N,N,N-trimethyl-4-(2-oxoborn-3-ylidenemethyl)-aniline methyl sulfate;
camphor benzalkonium methosulfate;
fatty amines;
betaines, e.g. cocamidopropyl betaine;
quats, e.g. ricinoleamidopropyltrimodium methosulfate, Quaternium 18 or cetyltrimethyl-ammonium bromide;
behenic acid and other organic acids, e.g. isostearic acid, citric acid monoglyceride or sodium methylcocoyl taurate;
phospholipids, e.g. phosphatidylcholine, phosphatidylserine or alkylamine oxide;
ceramides and pseudoceramides and phytosterols.
The last-mlentioned compounds impart oleophobic properties to the micronised UV filters.
The proportion of cationic or anionic compounds in the composite is from 0.001 to 5% by weight, preferably from 0.01 to 3% by weight, based on the weight of the UV filter(s).
The invention relates also to composites obtainable by melting at least one sparingly soluble or insoluble organic UV filter with-antioxidants.
For that purpose, the sparingly soluble or insoluble organic UV filter(s) is/are melted together with antioxidants, cooled and then micronised in customary manner.
Antioxidants suitable for use according to the invention include all organic substances having scavenger properties that can be melted together with organic UV filters. New micro-pigments are obtained that offer simultaneously UV protection and an antioxidative action on their surface. That property is desirable in the case of cosmetic sunscreens, because the influence of UV and light can bring about the formation of damaging free radicals both in formulations and on the skin, which can result, for example, in so-called Mallorca acne or in premature skin ageing. Providing the micronised UV filters with antioxidants, in addition to giving protection against UV damage, simultaneously provides protection against photo-chemical degradation of constituents of the sunscreen formulation.
The proportion of antioxidants in the composite is generally from 0.001 to 30% by weight, preferably from 0.01 to 3% by weight, based on the weight of the UV filter(s).
A content of antioxidants in micropigments is especially advantageous when the latter, comprise, in addition to organic UV filters, also the above-mentioned photocatalytically active inorganic micropigments, e.g. titanium dioxide, zinc oxide (also coated) or other suitable inorganic oxides, e.g. iron oxide.
The following compounds may be mentioned as examples of antioxidants:
tocopherols, e.g. xcex1-tocopherol (CAS 59-02-9), tocopheryl acetate, vitamin E succinate,
ellagic acid 
propyl gallate (CAS 121-79-9) 
N-butylated hydroxytoluene (BHT; CAS 128-37-0);
butylated hydroxyanisole (BHA);
2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)mesitylene (CAS 1709-70-2) 
tetrakis[methylene-3-(3xe2x80x2,5xe2x80x2-di-tert-butyl-4xe2x80x2-hydroxyphenyl)propionate]methane (CAS 6683-19-8);
the compound of formula 
the compound of formula 
vanillin;
ubiquinone;
ferulic acid and derivatives;
rutinic acid and derivatives;
urocanic acid and derivatives; and
propolis.
Preferably the following mixtures of antioxidants and organic UV filters are used:
mixtures of methylene bis-benzotriazolyl tetramethylbutylphenol, octyl triazone, titanium dioxide and tocopherol,
mixtures of 2,2xe2x80x2-methylene bis[6-(2H-benzotriazol-2-yl)-4-methyl-phenol, octyl triazone, tris-resorcinyl triazine and vitamin E
mixtures of methylene bis-benzotriazolyl tetramethylbutylphenol, octyl triazone, the compound of formula 
(xe2x80x9cFischer aldehydexe2x80x9d) and the compound of formula 
The invention relates also to composites obtainable by melting meltable cosmetic, plant-based and pharmaceutical active ingredients into organic UV filters.
In general it is possible to use micronised UV filters as carriers of highly active substances, especially cosmetic and/or pharmaceutical active ingredients. The advantage of such composites lies in the possibility of releasing the active ingredient(s) from the solids (slow release). Slow release ensures that highly active substances, e.g. anti-inflammatories, cosmetic active ingredients or trace elements, e.g. Zn2+ or Mg2+, are also uniformly effective over the entire period of use of the UV pigments.
Examples of active ingredients that may be used include:
active ingredients for providing antimicrobial properties and, simultaneously, anti-inflammatory action, e.g triclosan or diclosan;
anti-inflammatory active ingredients, e.g. famesol, panthenol and avocado oil;
active ingredients having a deodorant or antiperspirant action, e.g. zinc ricinoleates and alkyl citrates;
undecylenic acid and derivatives thereof (e.g. diethanolamides)
zinc undecylate;
pyrithiones, e.g. sodium pyrithione;
odorants or odorant mixtures incorporated by melting, e.g. menthol, geraniol etc., that impart a permanent odour of uniform intensity to such micropigments and to formulations comprising them.
For the preparation of the micropigment mixtures it is possible to use any known processes that are suitable for the preparation of microparticles, e.g.:
wet-grinding with a hard grinding medium, for example zirconium silicate and a protective surfactant or a protective polymer in water or in a suitable organic solvent;
spray-drying from a suitable solvent, for example aqueous suspensions or suspensions containing organic solvents, or true solutions in water, ethanol, dichloroethane, toluene or N-methylpyrrolidone etc..
by the expansion according to the RESS process (Rapid Expansion of Supercritical Solutions) of supercritical fluids (e.g., CO2) in which the UV filter(s) is/are dissolved, or the expansion of fluid carbon dioxide together with a solution of one or more UV filters in a suitable organic solvent;
by reprecipitation from suitable solvents, including supercritical fluids (GASR process=Gas Anti-Solvent Recrystallisation/PCA process=Precipitation with Compressed Anti-solvents).
As grinding apparatus for the preparation of the micronised organic UV absorbers according to the invention there may be used, for example, a jet mill, ball mill, vibratory mill or hammer mill, preferably a high-speed mixing mill. The grinding is preferably carried out with a grinding aid, for example an alkylated vinylpyrrolidone polymer, a vinylpyrrolidone/vinyl acetate copolymer, an acyl glutamate, an alkyl polyglucoside, ceteareth-25 or especially a phospho-lipid.
The micropigments and mixtures of micropigments so obtained generally have an average particle size of from 0.02 to 2 nm, preferably from 0.05 to 1.5 nm and more especially from 0.1 to 1.0 nm.
By virtue of their lipophilicity, they can satisfactorily be incorporated, alone or together with other soluble organic UV absorbers, into oil-containing and fat-containing cosmetic formulations, such as oils, O/W or W/O emulsions, fatty sticks or gels, in accordance with known methods.
Surprisingly, the formulations obtained have the same or better protective action when soluble UV absorbers are used in smaller amounts or even not at all.
The invention relates also to a cosmetic formulation comprising a mixture of micropigments, optionally one or more antioxidants and/or inorganic pigments and/or a cationic or anionic compound, and also cosmetically acceptable carriers or adjuvants.
Cosmetic formulations according to the invention may be contained in a wide variety of cosmetic preparations. Especially the following preparations, for example, come into consideration:
skin-care preparations, e.g. skin-washing and cleansing preparations in the form of tablet-form or liquid soaps, synthetic detergents or washing pastes;
bath preparations, e.g. liquid (foam baths, milks, shower preparations) or solid bath preparations, e.g. bath cubes and bath salts;
skin-care preparations, e.g. skin emulsions, multi-emulsions or skin oils;
cosmetic personal care preparations, e.g. facial make-up in the form of day creams or powder creams, face powder (loose or pressed), rouge or cream make-up, eye-care preparations, e.g. eyeshadow preparations, mascara, eyeliner, eye creams or eye-fix creams; lip-care preparations, e.g. lipsticks, lip gloss, lip contour pencils, nail-care preparations, such as nail varnish, nail varnish removers,nail hardeners or cuticle removers;
intimate hygiene preparations, e.g. intimate washing lotions or intimate sprays;
foot-care preparations, e.g. foot baths, foot powders, foot creams or foot balsams, special deodorants and antiperspirants or callus-removing preparations;
light-protective preparations, such as sun milks, lotions, creams and oils, sun blocks or tropicals, pre-tanning preparations or after-sun preparations;
skin-tanning preparations, e.g. self-tanning creams;
depigmenting preparations, e.g. preparations for bleaching the skin or skin-lightening preparations;
insect-repellents, e.g. insect-repellent oils, lotions, sprays or sticks;
deodorants, such as deodorant sprays, pump-action sprays, deodorant gels, sticks or roll-ons;
antiperspirants, e.g. antiperspirant sticks, creams or roll-ons;
preparations for cleansing and caring for blemished skin, e.g. synthetic detergents (solid or liquid), peeling or scrub preparations or peeling masks;
hair-removal preparations in chemical form (depilation), e.g. hair-removing powders, liquid hair-removing preparations, cream- or paste-form hair-removing preparations, hair-removing preparations in gel form or aerosol foams;
shaving preparations, e.g. shaving soap, foaming shaving creams, non-foaming shaving creams, foams and gels, preshave preparations for dry shaving, aftershaves or aftershave lotions;
fragrance preparations, e.g. fragrances (eau de Cologne, eau de toilette, eau de parfum, parfum de toilette, perfume), perfume oils or cream perfumes;
dental-care, denture-care and mouth-care preparations, e.g. toothpastes, gel toothpastes, tooth powders, mouthwash concentrates, anti-plaque mouthwashes, denture cleaners or denture fixatives;
cosmetic hair-treatment preparations, e.g. hair-washing preparations in the form of shampoos and conditioners, hair-care preparations, e.g. pretreatment preparations, hair tonics, styling creams, styling gels, pomades, hair rinses, treatment packs, intensive hair treatments, hair-structuring preparations, e.g. hair-waving preparations for permanent waves (hot wave, mild wave, cold wave), hair-straightening preparations, liquid hair-setting preparations, foams, hairsprays, bleaching preparations, e.g. hydrogentperoxide solutions, lightening shampoos, bleaching creams, bleaching powders, bleaching pastes or oils, temporary, semi-permanent or permanent hair colourants, preparations containing self-oxidising dyes, or natural hair colourants, such as henna or camomile.
The final formulations listed may be in a wide variety of presentation forms, for example:
in the form of liquid preparations as a W/O, O/W, O/W/O, W/O/W or PIT emulsion and all kinds of microemulsions,
in the form of a gel,
in the form of an oil, a cream, milk or lotion,
in the form of a powder, a lacquer, a tablet or make-up,
in the form of a stick,
in the form of a spray (spray with propellent gas or pump-action spray) or an aerosol,
in the form of a foam, or
in the form of a paste.
Advantageously the cosmetic formulations according to the invention may comprise further substances that absorb UV radiation in the UVB range. In that case the total amount of filter substances is from 0.1 to 30% by weight, preferably from 0.5 to 10% by weight, especially from 1 to 6% by weight, based on the total weight of the composition.
As additional UVB filters there come into consideration especially oil-soluble, non-micronised compounds, e.g. organic UV absorbers from the class of the p-aminobenzoic acid derivatives, salicylic acid derivatives, benzophenone derivatives, dibenzoylmethane derivatives, diphenyl acrylate derivatives, benzofuran derivatives, polymeric UV absorbers, comprising one or more organosilicon radicals, cinnamic acid derivatives, camphor derivatives, trianilino-s-triazine derivatives, phenylbenzimidazolesulfonic acid and salts thereof, menthyl anthranilates, benzotriazole derivatives, andlor an inorganic micropigment selected from TiO2, zinc oxide and mica, each encapsulated with aluminium oxide or silicon dioxide.
The following compounds are examples of p-aminobenzoic acid derivatives:
4-aminobenzoic acid (PABA); ethyldihydroxypropyl-PABA of formula 
PEG-25-PABA of formula 
wherein m, n and x have the same meanings and are each a maximum of 25;
octyldimethyl PABA of formula 
and glycyl amino-benzoate of formula 
The following compounds are examples of salicylic acid derivatives:
homomenthyl salicylate of formula 
triethanolamine salicylate of formula 
amyl p-dimethylaminobenzoate of formula 
octyl salicylate of formula 
and 4-isopropylbenzyl salicylate of formula 
The following compounds are examples of benzophenone derivatives:
benzophenone-3-(2-hydroxy-4-methoxybenzophenone), benzophenone-4-(2-hydroxy-4-methoxybenzophenone-5-sulfonic acid) and benzophenone-8-(2,2xe2x80x2-dihydroxy-4-methoxybenzophenone).
The following compound is an example of a dibenzoylmethane derivative:
butylmethoxydibenzoylmethane-[1-(4-tert-butyl)-3-(4-methoxyphenyl)propane-1,3-dione].
The following compounds are examples of diphenyl acrylate derivatives:
octocrylene (2-ethylhexyl-2-cyano-3,3xe2x80x2-diphenyl acrylate) and etocrylene (ethyl-2-cyano-3,3xe2x80x2-diphenyl acrylate).
The following compounds are examples of benzofuran derivatives:
3-(benzofuranyl)-2-cyanoacrylate, 2-(2-benzofuranyl)-5-tert-butylbenzoxazole and 2-(p-aminophenyl)benzofuran and especially the compound of formula 
The following compounds are examples of polymeric UV absorbers that contain one or more organosilicon radicals:
a benzylidene malonate derivative, especially the compound of formula 
wherein
R24 is hydrogen or methoxy and
r is approximately 7; the compound of formula 
The following compounds are examples of cinnamic acid esters:
octyl methoxycinnamate (4-methoxycinnamic acid 2-ethylhexyl ester), diethanolamine methoxycinnamate (diethanolamine salt of 4-methoxycinnamic acid), isoamyl p-methoxycinnamate (4-ethoxycinnamic acid 2-isoamyl ester), 2,5-diisopropylmethyl cinnamate and a cinnamic acid amido derivative.
The following compounds are examples of camphor derivatives:
4-methyl-benzylidene camphor [3-(4xe2x80x2-methyl)benzylidene-bornan-2-one], 3-benzylidene camphor (3-benzylidene-bornan-2-one), polyacrylamidomethylbenzylidene camphor {N-[2(and 4)-2-oxyborn-3-ylidene-methyl)benzyl]acrylamide polymer}, trimonium-benzylidene camphor sulfate [3-(4xe2x80x2-trimethylammonium)-benzylidene-bornan-2-one methyl sulfate], terephthalydene dicamphorsulfonic acid {3,3xe2x80x2-(1,4-phenylenedimethine)-bis(7,7-dimethyl-2-oxo-bicyclo[2.2.1]heptane-1-methanesulfonic acid} or salts thereof, and benzylidene camphorsulfonic acid [3-(4xe2x80x2-sulfo)benzylidene-bornan-2-one] or salts thereof.
The following compounds are examples of trianilino-s-triazine derivatives:
octyl triazine-[2,4,6-trianilino-(p-carbo-2xe2x80x2-ethyl-1xe2x80x2-oxy)-1,3,5-triazine, and the trianilino-s-triazine derivatives described in U.S. Pat. Nos. 5,332,568, 5,252,323, WO 93/17002 and WO 97/03642 and EP-A-0 517 104.
The following compound is an example of a benzotriazole:
2-(2-hydroxy-5-methyl-phenyl)benzotriazole.
The following Examples serve to illustrate the invention but do not limit the invention thereto. The cosmetic active substances are primarily given with their INCI name (INCI=International Norm of Cosmetical Ingredients).